Being able to find machine-payable endpoints is essential to building interesting applications both for machine and human consumption. To help with this, I wrote a directory service backed by a crawler and now with a text-based browser front-end.
The best intro is probably to use the endpoint browser. First, it will prompt you for confirmation and purchase the latest directory results for 250 satoshis. Then it will let you curl each endpoint through a menu. Get it from here, unzip the files and start it with: